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1、NORME EUROPENNE EUROPISCHE NORM Edition 1 March 1977 UDC 678.5/8:677.521:539.42 Key words: plastics, glass reinforced plastics, thermoplastic resins, thermosetting resins, tests, mechanical tests, tension tests, tensile strength, elongation at break, modulus of elasticity, tensile stress, test equip
2、ment, test specimens, testing conditions English version Glass reinforced plastics. Determination of tensile properties Matires plastiques renforces au verre textile. Dtermination des caractristiques en traction Glasfaserverstrkte Kunststoffe. Zugversuch This European Standard was accepted by CEN on
3、 1977-03-31. The CEN-members are bound to adhere to the CEN Internal Regulations which specify under which conditions this European Standard has to be given, without any alteration, the status of a national standard. Up-to-date lists and bibliographical references concerning such national standards
4、may be obtained on application to the CEN Central Secretariat or to any CEN member. This European Standard exists in three versions (English, French, German) recognized by CEN as equivalent. National versions in other languages rank as translations and in case of doubt shall be checked against one o
5、f the recognized versions. CEN members are the national standards organizations of Austria, Belgium, Denmark, Finland, France, Germany, Ireland, Italy, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. c European Committee for Standardization Comit Europen de Normalisatio
6、n Europisches Komitee fr Normung Central Secretariat: Rue de Brderode, 2, B-1000 Bruwels O Copyright reserved to all CEN members EN 61 Contents Cooperating organizations Brief history Foreword 1. Scope and field of application 2. Reference 3. Definitions 4. Apparatus 5. Test specimens 6. Preconditio
7、ning 7. Testing speeds 8. Procedure CEN EN*b1 77 3404587 0004323 4 Page Back cover 2 3 3 3 3 3 4 5 5 5 9. Expression of results 10. Test report Page 5 6 Figures 1. Chart of apparent extension (2) versus force (i) 3. Method of preparing test specimens with attached 6 2. Test specimens 7 end pieces 8
8、National appendix A Inside back cover -,-,- EN61 Page2 CEN EN*bl 77 m 3 Y O Y S B OOOY324 b Brief history This European Standard was drawn up by CEN Technical Committee 66 Testing of glass fibre reinforced plastics, the Secretariat of which is held by AFNOR. The contents of this standard were submit
9、ted for ballot to the members of CEN in November 1974 in view of its adoption as a European Standard. This European Standard was adopted by CEN as a result of its acceptance by the following member countries: Austria, Belgium, Denmark, France, Germany, Italy, Netherlands, Portugal, Spain, Sweden, Un
10、ited Kingdom. -,-,- . CEN EN*bL 77 3404583 0004325 8 Glass reinforced plastics. o Determination of tensile properties Foreword This standard is in technical agreement with Draft International Standard ISO/DIS 3268 Textile glass reinforced plastics - Tensile properties and includes the definitions fr
11、om IS0 Recommendation ISOIR 527 - 1966 Plastics - Determination of tensile properties. 1. Scope and field of application 1.1 This European Standard specifies a method of determining certain tensile properties of textile glass reinforced plastics. The method specified is not necessarily applicable to
12、 materials of very high tensile strength, for example unidirectional reinforced materials). The method is applicable to reinforced thermosetting resins and also to reinforced thermoplastics. Injection-moulded test specimens made from reinforced thermoplastics are subject to fibre orientation, and ma
13、y give values that are untypically high; however, they may be used if other methods of specimen preparation are impracticable. 1.2 The method describes the determination of the following tensile properties: -the initial tangent modulus of elasticity and the tensile secant modulus of elasticity (when
14、 it is not possible to determine the initial tangent modulus of elasticity, the tensile secant modulus of elasticity at 0.1 %strain is determined); - maximum tensile stress; NOTE. If there is a clean break the maximum tensile stress is the stress at break; in other cases it is the stress correspondi
15、ng to the maximum force. -the elongation at maximum force and, possibly, the elongation at break. The force-elongation curves at different temperatures, degrees of humidity and rates of strain yield interesting information concerning the behaviour of the materials. 1 . 3 It is only possible to obtai
16、n comparable values between different materials if identical test specimens are used. These should also be tested under well defined conditions of pretreatment, temperature, humidity and rate of strain. Finally, it is the aim of this method to obtain tensile results that can be used either for - qua
17、lity control, or - the preparation of specifications for materials. 2. Reference EN 62 - Glass reinforced plastics - Standard atmospheres for conditioning and testing. 3. Definitions 3 . 1 tensile stress. Tensile force per unit area of original cross section within the narrow parallel portion, carri
18、ed by the test specimen at any moment. 3 . 2 percentage elongation. Increase in the distance between reference lines on the narrow parallel portion of the test specimen, due to a tensile force, and expressed as a percentage of the initial distance between the reference lines. 0 EN 61 Page 3 3.3 plas
19、tic modulus. Ratio of stress to corresponding strain within the range of the greatest stress that the material is capable of sustaining without any deviation of proportionality of stress to strain, .e. the slope of the force-elongation curve obtained in the tensile test. In the portion of the curve
20、past the limit of proportionality, or if the limit does not exist, it is possible to determine: 3 . 3 . 1 initial tangent modulus, The slope of the tangent of the force-elongation at its origin (see note). NOTE. With some testing machines the curves show local divergences at the origin which make it
21、 impossible to draw the tangent. If this occurs it is necessary to adjust the position of the origin on the elongation axis (see figure 1). 3.3.2 secant modulus at x % elongation. Slope of the straight line passing through the origin (corrected, if necessary, as described in 3.3.1) of the force-elon
22、gation curve and the point of the curve corresponding to an apparent elongation of x %. 4. Apparatus 4.1 Testing machine, having a constant rate of traverse and comprising: (a) A stationary or substantially stationary member, with a suitable grip, and a movable member with a second grip. The grips s
23、hall be made so as to allow, at any moment, alignment of the axis of the test specimen along the direction of the applied force. This can be achieved, for example, by using centring pins in the grips. It is suggested that self-tightening grips be used so as to limit as completely as possible any sli
24、pping of the test piece in the grips. (b) A drive mechanism, giving the movable member a uniform rate of traverse under no load conditions, the speed being as indicated in clause 7. (c) A force indicating mechanism (dynamometer), showing the force applied to the test specimen held in the grips. This
25、 mechanism shall be essentially without inertia a t the speed of testing and shall indicate the force with an accuracy of within 1 % of the indicated value. The fixed and movable members, the drive mechanism and the grips shall be constructed of such materials and be of such dimensions that the tota
26、l elastic longitudinal strain of these devices is not greater than 1 % of the longitudinal strain shown simultaneously in the gauge length of the test specimen; these requirements shall be satisfied for any force less than or equal to the rated capacity of the testing mach ne. 4.2 Extension indicato
27、r, permitting the determination, at any time during the test, of the distance between two fixed points (or reference marks) located within the central parallel portion of the test specimen. Other techniques are not allowed; in particular, the measurement of strain by the displacement of the grips is
28、 forbidden. It is highly desirable that the extensometer used should allow a force-extension curve to be drawn. NOTE 1. Some optical devices can be used which make it possible to follow the separation of the two reference marks. Other extensometers (mechanical or volumetric) may be used provided tha
29、t they can measure strain with an accuracy of 1 % or better. NOTE 2. The extensometer should not damage the test specimens; in particular, by causing breaks where it is attached. A new document for the testing of roving laminates (unidirectionaii-is under 5tudy and when completed will be integrated
30、into this European Standard. -,-,- CEN EN*bL 77 E EN 61 Page 4 The initial distance between the two fixed points, which is called the gauge length shall be known with a precision of 1 %. The elongation should be recorded automatically as a function of the force or ot the elapsed time from the beginn
31、ing of the test. In this latter case, the force as a function of elapsed time shall also be recorded. The extensometer should be essentially without inertia at the speed of testing. It should be accurate to within 1 % of the indicated strain. The recommended gauge length is 50 mm for test specimens
32、of type 1 and 100 mm for the other types. However, a shorter distance may be used, provided that the above tolerances are taken into account. 4.3 Micrometer, suitable for measuring the dimensions of the test specimen to within f 0.01 inm. 5 . Test specimens 5.1 Types and choice of test specimen. Thr
33、ee types of test specimen may be used, as illustrated, together with a table of dimensions, in figure 2. Type I is for testing glass reinforced thermoplastics, type I I (rectangular, without end pieces) and type I II (rectangular, with parallelepipedic end pieces) are for testing glass reinforced th
34、ermosets. Type I specimens may also be used for glass reinforced thermosets if they break within the gauge length. The preferred width of test specimens of types I1 and I I I is 25 mm; widths of 50 mm or greater may be used if the tensile strength is low due to the reinforcement used. The thickness
35、of the test specimen shall be between 2 and 10 mm. To decide between test specimens of types II and I II first carry out tests with a specimen of type I I and if the test is not possible or not satisfactory (slipping or breaking in the grips, etc. (see 5.3) use specimens of type I I I. 5.2 Preparati
36、on 5.2.1 General. If a comparison is to be made between different reinforced thermosets, cut the test specimens out of flat sheets. If test specimens are to be cut from finished parts (for 340Li587 0004326 T M Attach the strips, as shown in figure 3, as follows: (1) rub all surfaces to which adhesiv
37、e will b e applied, with fine abrasive paper; (2) carefully clean these surfaces with a suitable solvent; (3) for sticking, use a cold hardening adhesive (for example an epoxide adhesive), strictly following the manufacturers instructions; (4) keep the assembled parts under pressure for a sufficient
38、 time. It is desirable that the adhesive used for bonding be of a flexible nature with an elongation at break greater than that of the material under test. The strips shall be perfectly superposed at each end, parallel with each other and normal to the length direction of the test specimens. The she
39、ets together with the strips constituting the end pieces are the test blanks ready for cutting into test specimens. 5.2.3 Machining of the test specimens NOTE. In all cases: -avoid working under conditions that would create too great a heat build-up in the test specimen; it is recommended that a coo
40、lant be used; if a coolant is used wipe the test specimens clean immediately after machining; - check that the sides of the test specimen are free from defects. 5.2.3.1 Type test specimens (type I). Reinforced thermoplastics test specimens are usually subject to fibre orientation if moulded. It is,
41、therefore, advisable in most cases to machine the specimens from compression moulded rectangular sheets by means of a small grinding wheel or router made of a suitable material and following a template. 6 . 2 . 3 . 2 Rectangular test specimens (type I I and type I I I 1. These can be cut by means of
42、 a diamond or carborundum saw. 5.3 Number of test specimens. Glass reinforced plastics are usually anisotropic. It is, therefore, often of interest to cut test specimens according to at least the two main directions of anisotropy, or according to directions previously specified example, quality cont
43、rol during manufacture or on delivery), (for example lengthwise Or to the sheet). they should preferably be taken from flat areas or areas of. minimum curvature. Furthermore, every effort shall be made to use test specimens without surface machining specifically intended to reduce their thickness. I
44、f the surfaces of the specimens have been machined to reduce their thickness, the results obtained will not be comparable with those obtained on test specimens without machined surfaces. 5.2.2 Preparation and application of end pieces (for type II I test specimens). A recommended method is as follow
45、s: cut out, from the material under test, a sheet having the length of the intended test specimens, and of a width suitable for the number of test specimens required. To form the end pieces, cut parallelepipedic strips, preferably from a material having a modulus of elasticity smaller than that of t
46、he material under test, of a width such that, during testing, the distance between the grips will be at least 20 mm greater than the distance between the end pieces. NOTE. For making the end pieces, it is possible to use strips of a thickness one to three times that of the material to be tested. _ F
47、or each direction and property considered (modulus of elasticity, tensile strength, etc.), at least five results are necessary. Discard and replace any test specimens which have: - slipped in the grips; - broken in the grips or at a distance less than 10 mm from the grips; NOTE. However, if the majo
48、rity of test specimens break in this manner, the results should be evaluated statistically to determine whether or not they represent a homogeneous population. - undergone testing under faulty operating conditions, or have given manifestly inconsistent results for evident reasons. The number of meas
49、urements could even be greater if a greater precision of the mean value is required. It is possible to evaluate this by means of the confidence interval (95 % probability). O a a * CEN EN*LL 77 m 3409589 0009327 L m EN 61 Page 5 6. Preconditioning The test specimens shall be conditioned as required by the particular specification of each reinforced plastics material tested. If no specification exists, condition the test specimens for te